Lỗi ứng dụng khi nâng cấp cơ sở dữ liệu sqlite lần đầu tiên

Question

ứng dụng của tôi gặp sự cố khi cơ sở dữ liệu sqlite được cập nhật lần đầu tiên. Tải lại ứng dụng, nó hoạt động tốt từ đó trở đi. Tôi đoán điều này đã làm với chức năng onUpgrade sau đó. Tôi dường như không thể xác định được vị trí của vấn đề, mọi lời khuyên rất được đánh giá cao. Cảm ơn trước.

DatabaseHelper:

public class DatabaseHelper extends SQLiteOpenHelper { 

    private static String DB_PATH = "/data/data/jp.atomicideas.ne/databases/"; 
    private static String DB_NAME = "dataset"; 
    public static final int DB_VERSION = 2; 
    private SQLiteDatabase myDataBase; 
    private final Context myContext; 
    public static final String EXPRESSION_TABLE = "expression"; 

    /** 
    * Constructor 
    * Takes and keeps a reference of the passed context in order to access 
    * the assets and resources. 
    * 
    * @param context 
    */ 
    public DatabaseHelper(Context context) { 
     super(context, DB_NAME, null, DB_VERSION); 
     this.myContext = context; 
    } 

    /** 
    * Creates an empty database on the system and rewrites with database from app 
    * @throws IOException 
    */ 
    public void createDataBase() throws IOException { 
     boolean dbExist = checkDataBase(); 
     // if the database already exists, do nothing 
     if(dbExist){ 
      Log.v("DB Exists", "db exists"); 
      // by calling this method here, onUpgrade will be called on a writeable db, if version number is bumped 
      this.getWritableDatabase(); 
     } 
     dbExist = checkDataBase(); 
     // if the database doesn't exist, copy the application's database to be used 
     if(!dbExist) { 
      this.getReadableDatabase(); 
      try { 
       copyDataBase(); 
      } catch (IOException e) { 
       throw new Error("Error copying database"); 
      } 
     } 
    } 

    /** 
    * Check if the database already exists to avoid re-copying the file 
    * @return true only if it exists, falls if it doesnt 
    */ 
    private boolean checkDataBase() { 
     SQLiteDatabase checkDB = null; 

     try { 
      String mypath = DB_PATH + DB_NAME; 
      checkDB = SQLiteDatabase.openDatabase(mypath, null, SQLiteDatabase.OPEN_READONLY); 
     } catch(SQLiteException e) { 
      // database does not exist yet 
     } 

     if(checkDB != null) { 
      checkDB.close(); 
     } 

     return checkDB != null ? true : false; 
    } 

    /** 
    * Copies database from the local assets folder to the system folder 
    * @throws IOException 
    */ 
    private void copyDataBase() throws IOException { 

     // Open the app database file as the input stream 
     InputStream myInput = myContext.getAssets().open(DB_NAME); 

     // Path to the empty temporary database to be replaced 
     String outFileName = DB_PATH + DB_NAME; 

     // Open the empty database file as the output stream 
     OutputStream myOutput = new FileOutputStream(outFileName); 

     // Transfer bytes from the input file to the output file 
     byte[] buffer = new byte[1024]; 
     int length; 
     while ((length = myInput.read(buffer)) > 0) { 
      myOutput.write(buffer, 0, length); 
     } 

     // Close the streams 
     myOutput.flush(); 
     myOutput.close(); 
     myInput.close(); 

    } 

    public void openDataBase() throws SQLException { 

     // Open the database 
     String myPath = DB_PATH + DB_NAME; 
     myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY); 
    } 

    @Override 
    public synchronized void close() { 
     if(myDataBase != null) 
      myDataBase.close(); 
     super.close(); 
    } 

    @Override 
    public void onCreate(SQLiteDatabase db) { 

    } 

    @Override 
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 

     Toast.makeText(myContext, "onUpgrade called!", Toast.LENGTH_LONG).show(); 

     if (oldVersion < newVersion) { 
      Log.v("Database Upgrade", "Database version higher, upgrading"); 
      myContext.deleteDatabase(DB_NAME);       
     } 
    } 

} 

Và đây là sản phẩm LogCat:

06-28 20:52:07.638: V/DB Exists(26580): db exists 
06-28 20:52:07.658: V/Database Upgrade(26580): Database version higher, upgrading 
06-28 20:52:07.658: I/Database(26580): sqlite returned: error code = 1802, msg = statement aborts at 3: [PRAGMA user_version = 2] 
06-28 20:52:07.658: E/Database(26580): Failure 10 (disk I/O error) on 0x33a3f0 when executing 'PRAGMA user_version = 2' 
06-28 20:52:07.658: I/Database(26580): sqlite returned: error code = 1, msg = statement aborts at 2: [ROLLBACK;] cannot rollback - no transaction is active 
06-28 20:52:07.658: E/Database(26580): Failure 1 (cannot rollback - no transaction is active) on 0x33a3f0 when executing 'ROLLBACK;' 
06-28 20:52:07.658: D/Database(26580): exception during rollback, maybe the DB previously performed an auto-rollback 
06-28 20:52:07.668: D/AndroidRuntime(26580): Shutting down VM 
06-28 20:52:07.668: W/dalvikvm(26580): threadid=1: thread exiting with uncaught exception (group=0x2aac8578) 

VÀ

06-28 20:52:07.678: E/AndroidRuntime(26580): Caused by: android.database.sqlite.SQLiteDiskIOException: disk I/O error: PRAGMA user_version = 2 

Answer 1

Bạn không cần phải xóa các cơ sở dữ liệu, chỉ cần sao chép trên nó sử dụng phương pháp bạn đã xác định là (copyDataBase), như sau:

@Override 
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
    Toast.makeText(myContext, "onUpgrade called!", Toast.LENGTH_LONG).show(); 
    if (oldVersion < newVersion) { 
     Log.v("Database Upgrade", "Database version higher, upgrading"); 
     try { 
      copyDataBase(); 
     } catch (IOException e) { 
      throw new Error("Error upgrading database"); 
     } 
    } 
}